## Alphabet ab - 𐎀 (ʾa) + 𐎁 (b). From Proto-Semitic ʾab-, meaning "father." It’s one of the oldest and most stable words in Semitic languages - appearing across Northwest and East Semitic branches with almost no phonetic change. In Ugaritic texts, ʾab appears frequently in divine titles such as ʾab šnm (“Father of Years”) referring to the god El, the high god and patriarch of the pantheon. It could denote both literal and figurative paternity — e.g., “ancestor,” “creator,” or “chief.” cd - Unix, for change directories. ef gh - The phoneme /f/, in certain corners of english orthography/ghonetics. ij - Index variables, in the Old Mathematics pre-20XY in which types are vague "which letter are we using" vibes based intuitions. - Infinite Jest. A rare example of simple straightforward but (rarely) non-retarded writing in the sense of non-constant genre, the constant version of which is the referent of the aforementioned euphemism (anti-sic) "retarded." kl - Kullback-Leibler divergence. mn - Two letters with a shared history of fourier-ish squiggledom. op qr st uv wx yz